Topic 2: Skeletal System

Question 1

What is the basic functional unit of a bone

Answer 1

Haversian system

Question 2

What items run through the central canal of a osteon (haversian system)

Answer 2

Blood vessels
Nerves
Lymph nodes

Question 3

Please describe the functions of the three types of cells (osteoblasts, osteocytes, and osteoclasts) in the development of bone.

Answer 3

Bone is produced by osteoblast cells. This is the early version of bone cells
• These cells secrete collagen fibres which is soft intercellular matrix of the bones.
• The osteoblasts then harden the matrix by adding in calcium and phosphate.
• As they harden the matrix, the osteoblasts become trapped in tiny spaces called lacunae.
osteoblast cell is then called osteocytes.
• Canaliculi (small tube) connect the osteocytes
to each other and to the blood vessels.
• If an injury to a bone occurs, its osteocytes readily revert to osteoblasts to carry out the repair.
• Osteoclast cells: responsible for reabsorbing materials and for the remodeling of bone, e.g. after a fracture

Question 4

• What are the major differences of compact and cancellous (spongy) bones?

Answer 4

Strength: compact bones: solid and hard, cancellous bones: less solid and hard then compact bones
Osteon: compact bones: Haversian systems are densely packed together, cancellous bones: no patrons but meshwork of bony sponge
Bone marrow: compact bones: no bone marrow, cancellous bones: filled with red bone marrow
Places: compact bones: usually found in the outer layer of all types of bones, cancellous bones: usually found in the ends of long bones and in the im core of short, irregular and flat bones

Question 5

What is the membrane covering outer and inner surfaces of bones called

Answer 5

Periosteum and endosteum

Question 6

How does blood vessels, lymphatic vessels and nerves enter the bone

Answer 6

Through an opening called the nutrient foramen

Question 7

What are the functions of bones

Answer 7

Support the body
• Provide leverage for muscle contraction, which
brings about movement
• Protect the organs, e.g. heart, lungs, brain
• Maintain calcium and phosphorus levels in the body.
• Blood cell formation – the bone marrow serves as sites for haematopoiesis (formation of blood)

Question 8

What are the different classification of bone

Answer 8

Long bone
Flat bone
Short bone
Irregular bones

Question 9

• What is the basic structure of a typical vertebra?

Answer 9

Consists of cylindrical body, tunnel like sructure called vertebral foramen that make up the spinal canal when joining t together . Has a dorsal projection called the sinuous proceSs and 2 projections from the side known as the transverse process

Question 10

What is the name of the structure between the bodies of each pair of vertebrae?

Answer 10

Intervertebral disk

Question 11

What are the key characteristics of these two cervical vertebrae (one for each)?

Answer 11

Atlas: wing
Axis: large blade like spinous process

Question 12

What are the key characteristics of the thoracic vertebrae, lumbar vertebrae, and sacral vertebrae (just one for each)?

Answer 12

Thoracic vertebrae: tall spinous process
Lumber vertebrae: large bodies
Sacral vertebrae: three vertebrae fused together to for, sacrum

Question 13

How many ribs directly attach to sternum? Is the bony part of a rib connecting to sternum or the cartilage part connecting to sternum

Answer 13

9 pairs of ribs directly attached to sternum
Cartiledge part

Question 14

What is the lass sternum bone called

Answer 14

The xiphoid process

Question 15

What is the name of the anatomical structure that the head of the femur sits in

Answer 15

Acetabulum

Question 16

What are the different degrees of movement for the three different types of joints?

Answer 16

Fibrous joint: immovable (skull)
Cartilaginous joints: limited movements (joints between the body of vertebraes
Synovial joints: plenty of movement

Question 17

Please describe the structure of a Synovial Joint.

Answer 17

allows plenty of movement
* A synovial joint is a connection between
two bones consisting of a cartilage-lined cavity
filled with fluid
* The bones are separated by a space, called
joint cavity.
* The joint cavity is lined by the synovial
membrane
* The synovial membrane secretes synovial fluid
into the cavity to provide lubrication and nutrition
* A joint capsule surrounds the whole joint to
provide protection.
* The joint is further stabilized by ligaments

Question 18

What are the main differences between dogs and birds in terms of the skeletal system?

Answer 18

Birds bone is lightweight (bones ar much thinner and many of the long bones are hollow)
Birds have pneumatic bones: many of the larger bones in birds are pneumatic means that they are filled with air contained in membranous air sacs the are connected with the respiratory system